This invention relates to apparatus for precisely and stably aligning a surface, and more particularly to an improved apparatus for precisely aligning optical surfaces such as, for example, a reflecting surface of a gas laser. While my invention is not necessarily limited to laser applications, it is particularly well suited therefore, and the specific embodiment of my invention will be described in this context.
In the prior art there are a large number of methods and apparatus for aligning optical surfaces. In general, it is relatively easy to provide coarse alignment. But it is relatively difficult to precisely align a surface, such as the reflective surface in a gas laser. Such applications require a very high precision--on the order of 2 arc seconds--along two mutually perpendicular axes.
Prior art in alignment mechanisms of the class contemplated by this invention usually are an assembly of multiple piece parts, and frequently have two or three pivots about which the surface to be aligned is rotated and several loosely constrained springs to hold the surface against some adjustable stops. In such prior art the aligned surface experiences minute angular and translational motions and uncertainties, due to relative motions between the parts in the assembly when the assembly is adjusted or when external vibrations are experienced. The object of this invention is to provide a relatively simple, sensitive and stable apparatus for angularly aligning a surface with respect to another surface.